A molecular orbital is introduced as a concept to simulate the behavior of an electron, as expressed as the probability of finding an electron in any specific region. Hence, a molecular orbital distribution is one of the important factors that determine electrochemical properties of a material. Molecular orbitals, which account for the distributions of electrons in a specific region in a molecular structure as a probability concept, cannot be obtained experimentally, but can be constructed using quantum mechanics.
Distribution patterns of molecular orbitals in a molecular structure are numerous and complex. For example, molecular orbitals (1) may be limited to the center of an entire molecular structure, (2) may exist only on a periphery distal to the center of a molecular structure, (3) may be found at regions near and distal to the center of a molecular structure, or (4) may be distributed across the entire molecular structure, but unevenly depending on specific regions. As such, the understanding of molecular orbital distribution tendency is prerequisite for the behavior of electrons in a molecular structure. Accordingly, a quantitative method is necessary for accurately evaluating molecular orbital distribution in an intuitive manner.
To date, there are no methods of evaluating and analyzing molecular orbital information, except for qualitative methods in which diagrams are created and compared in a visual manner. At present, however, such qualitative methods are not systematically utilized for the development of materials or the evaluation of physical properties. Considering the importance of the information that molecular orbitals, which account for electron behaviors, provide, molecular orbitals, if quantitatively and systematically analyzed like other quantitatively analyzable electrochemical properties, are expected to be greatly useful for developing materials or evaluating physical properties. Therefore, there is a need for a method for precisely evaluating molecular orbital information in a quantitative manner.